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Patented Apr. ll, I899.

'No. 622,9l4.

W. F. DAVIS.

GRINDING MILL.

(Application filed May 6, 1898.)

2 Sheets$haat I.

(No Model.)

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W'. F. DAVIS.

GRINDING MILL.

(Application filed may 8, 1898.)

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NrrED STATES PATENT OFFICEG \VILLIAM F. DAVIS, OF VVATERLOO, IOWA, ASSIGNOR TO THE DAVIS GASOLINE ENGINE VVO RKS COMPANY, OF SAME PLACE.

GRINDING-MILL.

SPECIFICATION forming part of Letters Patent No. 622,914, dated April 11,1899.

Application filed May 6, 1898- Serial No, 679,881- (No model.)

To all whom it may concern:

Be it known that I, WILLIAM F. DAVIS, a resident of Waterloo, in the county of Black Hawk, State of Iowa, have invented certain new and useful Improvements in Grinding Mills, of which I do declare the following to be a full, clear, and exact description, sufficient to enable others skilled in the art to make and use the same.

The present invention has relation to that class of grinding mills commonly known as feed-mills, such mills being more especially adapted for the grinding of corn or other grain to be used as food for stock, and particularly does the invention relate to the class of feed-mills known as duplex mills.

In the construction of the class of duplex mills to which my invention more particularly relates it has been heretofore the practice to provide a stationary inner shell or cone, and

over this stationary cone was mounted a revoluble cone or shell provided at its base with an inner grinding-ring that cooperated with an outer grinding-ring upon the stationary cone and provided upon its outer surface with an outer grinding-ring that cooperated with a grindin g-rin g held by bolts outside the revoluble cone. An example of this type of duplex mill is illustrated in Letters Patent No. 604,853, granted for an invention of Thomas Oascaden, Jr., May 31, 1898.

In order to regulate the grinding action of the grinding-rings in the duplex mills of prior constructionsuch, for example, as the mill set forth in the above-mentioned Cascaden patent-it has been the practice to pass bolts through lugs at the base of the inner station- 'ary cone or shell and up through similar lugs formed upon the outer ring that carried the outermost grinder, the inner shell being-also connected by a tripod with a temper-screw or adjustingrscrew that passed up through the center-post of the mill. The screw-bolts connecting the lugs of the inner stationary cone or shell with the lugs upon the outer grinding-ring were relied upon not merely to sustain the outer ring, but also to effect its adjustment, the adjustment of the inner shell or grinder being secured by means of the temperscrew. While this prior construction possesses many advantages over other forms of mills, in practice it is found difficult to so sustain the grinding-rings in position as to secure uniformity of adjustment and uniformity in the grinding action. In the construction of this class of mills, the grinders being formed as plain cheap castings, it follows that the grinding-rings are frequently not truly concentric, and in some instances the eccentricity of the rings amounts to onehalf or three-quarters of an inch. I-Ience it is that although the adjusting-bolts may be accurately set, still the eccentricity of the rings results in an uneven grinding, since the bolts do not permit of an automatic shifting or adjustment of the rings to compensate for their eccentricities. Moreover, with prior constructions of duplex mills the necessity of separate adjustment for the inner and outer grinding-shellsviz'., the temper-screw and the adj usting bolts -is objectionable, because of the danger of inequality of adjustment of the bolts or the danger of their working loose.

The present invention has for its object to overcome the objections above noted and to provide a simple, cheap, durable, and effective construction of mill that can be readily set up and managed by the unskilled labor commonly used in the operation of this class -of mills.

In carrying out my invention I sustain the grinding-rings from the top of the mill, and the several rings are so sustained from such point as to allow each pair of rings to ad just themselves independently of the others. Moreover, the point of connection or suspension of the rings at the top of the mill is'more or less loose, so that the rings can have a slight lateral swing or movement in order to compen'sate for any eccentricity in their shapes and consequent irregularity in movement.

In the accompanying drawings I have shown my invention as applied in two forms of duplex mills, in one of which the innermost and outermost grinders are revoluble, while the intermediate grinding-rings and supporting-shell are stationary, and in the other form the innermost and outermost grinders are stationary and the intermediate grinders and their sustaining-shell are revoluble. In both forms of my invention,however, it will be seen that the grinding-rings located about the base of the mill being sustained with respect to each other from the top of the mill,and consequently at a distance from their operative su rfaces,there is more or less lateral swing or movement allowed to the grinders to compensate for inequalities of surface or eccentricity in the shape of the rings.

Referring to the accompanying drawings, Figure 1 is a View in central vertical section through a grinding-mill embodying my invention. Fig. 2 is a plan view of the mill with the hopper removed. Fig. 3 is 'a detail View showing the center-post or cone-post of the mill. Fig. 4: is a view similar to Fig. 1, but illustrating a modified embodiment of the invention. Fig. 5 is a plan view of the construction shown in Fig. 4:.

A designates the inner shell or cone of the mill, the base portion of which has its periphery provided with grinding teeth or ribs a of usual or suitable construction and arrangement. The upper portion of the cone A is provided with crushing-teeth b in suitable number and arrangement, these teeth being adapted to cooperate with corresponding teeth 0, that depend from the arms C, that are preferably formed integral with and extend inwardly from the intermediate shell 0 of the mill. The intermediate shell 0 is of conoidal shape,and the interior of its base is furnished with a grinding-ring C and with teeth that cooperate with the grindingteeth a, formed upon the outer surface of the base of the inner shell A. At the bottom of the intermediate shell C are formed lugs D, that will be bolted to the top of the receivingbox or other convenient support in any suitable manner. From the center of the inner cone or shell A rises the cone-post A, the lower .portion of which is preferably of con ical contour, as shown in Fig. 3, and this conepost A passes upward through a corresponding conical or circular opening in the hub 0 that connects the arms 0, that project from the body of the intermediate shell 0. Around the intermediate shell 0 extends an outer shell E, the interior surface of the base of which is provided with a grinding-ring e, that cooperates with the grinding ring or teeth 0 formed upon the exterior of the lower part of the intermediate shell 0 From the upper part of the outer shell E extend inwardly the arms E, that are united to a hub E that is formed with a polygonal opening to receive the corresponding polygonal upper portion of the cone-post A. The arms E are cob-crushing arms and cooperate in the usual manner with the arms 0 beneath them. From the top of the shell E rises a hopper E, into which the ears of corn or like grain to be ground will be delivered. Revolution will be impartedto the outermost shell E by suitable sweeps (not shown) that will be attached to the lugs or studs E projecting laterally from the upper part of the outer shell E, and inasmuch as the outer shell E is connected with the cone-post A by the hub E it is manifest that rotation will -be imparted from the shell E to the cone-post the plate H. It will thus be seen that the screw- F (the upper end of which is furnished with a suitable hand-wheel f) serves not only to sustain the inner cone or shell A, but also by means of this screw the adjustment of both the inner and outermost shells and grinders with respect to the intermediate shelland its grinder can be effected. The intermediate shell 0 is-formed with aseries of openings 0 through which grain will pass outwardly to the outer set of grinders that is to say, between the lower portions of the intermediate shell 0 and the lower portion of the outer shell E.

From the foregoing description it will be seen that when grain is placed within the hopper E and rotation is imparted (by the sweeps that will be attached to the lugs E to the outer shell E corresponding rotation will be imparted to the inner shell A, the intermediate shell O and the grinders at the base thereof remaining stationary. The grain will pass downward between the arms E and O, thence between the teeth a and b, and finally a portion of the grain will pass outward between the grinding-rings a and 0 while a portion of the grain will pass through the opening 0 and thence downward between the grinders e and 0 The proper adjustment of the inner and outer shells A and E with respect to the intermediate shell 0' can be readily effected by means of the screw F, and inasmuch as the grinders at the base of the shells are sustained from the bearings at the tops of the shells the grinders will adjust themselves, and thus compensate for any imperfection in the castings,which in this cheap class of mills are seldom or never accurately round or of even thickness. This adjustment of the inner and outer grinding-shells at one operation and by a single screw is a feature of material advantage, and by sustaining the inner and outer shells at their tops and at a distance from the grinding-rings, so that a measure of movement is permitted to allow the grinders to adjust themselves to irregularities,the danger of breakage of parts is avoided, while at the same time the lateral movement or swing of the grinding-rings insures an even grinding of the grain, notwithstanding such irregularities orimperfections in construction.

. In duplex mills in which bolts are employed around the bottom for sustaining and adjusting the outermost grinding-ring it is manifest that any irregularity in the adj ustment of the several bolts would destroy the proper operation of the mill, whereas when a single temper-screw is employed, as in my present construction, all danger of inequality of adjustment is avoided, since the screw effects the entire adjustment of the grinders, and the lateral play or swing of the grinders from the top support compensates for irregularities or defects of construction.

While in the preferred embodiment of the invention the innermost and outermost shells of the mill are revoluble while the intermediate shell is stationary, still it is obvious that the broader features of my invention may be practiced in a mill in which the intermediate shell is revoluble and the innermost and outermost shells are stationary. Thus by reference to Figs. 4 and 5 it will be observed that the innermost shell A is provided at its lower edge with laterally-eXtending lugs a by which it will be bolted to the box or casing that receives the material passing from the mill. The cone-post or center post A passes up through the hub of the intermediate shell C, being conical at such point, while the upper polygonal portion of the cone-post enters the hub E of the outermost shell E. Consequently the innermost and outermost shells remain stationary. The bottom of the intermediate shell Eis provided with laterally-extended arms (2 and c", to one of which will be bolted the main shaft of a sweep and to the other of which will be bolted a stay-rod E leading from the outer end of the sweep. Except in the particulars above noted the construction of the mill last described will be the same as that illustrated upon Sheet 1 of the drawings. It will be seen that the intermediate shell E will be revolved by means of the sweep and the innermost and outermost shells will remain stationary; but the grinding-rings around the base of the mill being sustained from the top-post, so that a measure of lateral play or movement is allowed, it is manifest that the rings will adjust themselves to compensate for irregularities of construction, and thus insure evenness and uniformity in the grinding operation.

It is manifest that the details of construction above set out may be varied without departing from the spirit of the invention, the leading features of which are, first, the supporting of the grinding-rings from the top of the mill by loose connections, so that a meas ure of lateral play of movement is allowed to the rings, and, second, the use of a single adj Listing-screw, whereby the adjustment of the grinders is effected.

Having thus described my invention, what Iclaim as new, and desire to secure by Letters Patent, is-

1. A grindingmill of the character described comprising an inner cone provided with a grinding-ring at its base and provided at its top with a central post or support, an outer shell provided at its base with a grinding-ring and mounted upon said post or support in manner permitting a lateral swing to the grinding-ring of said shell and an intermediate cone-shell provided at its base with inner and outergrindingsurfaces and provided at its top with a hub encircling said cone post or support in manner permitting a lateral swing of the grinding-surfaces of said coneshell whereby any eccentricity in the shapes of or any irregularityin the movement of the grinding-rings is compensated for.

2. A grindingmill of the character described comprising an inner cone provided with a grinding-ring at its base and provided at its top with a hollow central post or support, an outer shell mounted upon said post in manner permitting said shell to swinglaterally and provided at its base with a grinding-ring, an intermediate cone-shell provided at its base with inner and outer grinding-surfaces cooperating respectively with the grinding-surfaces of the bottoms of the inner cone and outer shell and provided at its top with a hub loosely encircling said post or support and a temper-screw passing through said post or support, whereby the adjustment of the grinders at the base of the mill is effected.

3. A grinding mill of the character described comprising an inner revoluble cone provided with a grinding-ring at its base and provided at its top with a central post or support, an outer shell connected at its top with said cone postor support of the inner shell and revoluble therewith, and an intermediate stationary cone-shell provided at its top with a hub loosely encircling said cone-post and provided at its base with inner and outer grindingsurfaces cooperating respectively with the grinding-surfaces at the bottoms of the inner cone of the outer shell.

4. In a grinding-mill of the character described, the combination of an inner grinding-cone provided at its base with a grindingsurface and having its upper part provided with teeth, of an outer shell free at its bottom whereby it may swing laterally and connected at its top to the inner shell so as to revolve therewith and provided at its base with a grinding-surface, and an intermediate stationary cone-shell located between the inner and outer shells, said stationary cone-shell having its upper portion provided with teeth to cooperate with the teeth upon the upper portion of the inner cone and being provided at its bottom with inner and outer grindingsurfaces to cooperate with the corresponding grinding-surfaces at the bottoms of the inner cone and outer shell.

5. A grindingmill of the character de scribed comprising an inner cone provided with a central .post or support, an outer shell connected to said post or support of the inner cone and adapted to revolve therewith,

an intermediate grinding cone-shell provided plates and hearings to engage the inner cone with a hub through which the post of the inand outer shell whereby said parts may be ner cone projects, said inner cone, said outer simultaneously adjusted.

shell and said intermediate cone-shell being v VILLIAM F. DAVIS. providedat their bottoms with grinding-sun Vitnesses:

faces,and an adjnstingscrew passing through JOHN T. SWIFT,

said central cone-post and provided with JOSEPH A. PIERCE. 

